1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device.
2. Description of the Related Art
Conventionally, a semiconductor device is manufactured in such a manner that, for example, a plurality of semiconductor elements are formed on the first surface of a silicon wafer (semiconductor substrate), and the silicon wafer is subjected to dicing so as to separate the semiconductor elements (silicon chips) from each other. Between the step of forming semiconductor elements on the silicon wafer and the step of dicing, there is a step of grinding the silicon wafer so that the thickness of the separated silicon chips can be reduced to a desired value. When the silicon wafer is ground, a protection tape is adhered to one surface of the silicon wafer and then the opposite surface of the silicon wafer is ground by a grinding wheel.
After the completion of grinding the silicon wafer, the protection tape which is adhered onto the silicon wafer is irradiated with ultraviolet light so as to reduce the adhesive property, and the protection tape with reduced adhesive property is peeled off from the silicon wafer. At the same time, the silicon wafer is attached onto a dicing tape. In the above steps, the silicon wafer is attracted and conveyed by a vacuum suction device.
Recently, there has been an increasing demand for reducing the thickness of the silicon wafer and the silicon chip. However, as the thickness of the silicon wafer is reduced, a problem arises in which the silicon wafer is warped. Especially if the surface of the silicon wafer, which is opposite to the surface on which the semiconductor elements are formed, is ground while the protection tape is adhered onto the silicon wafer, the silicon wafer tends to warp badly. When the silicon wafer is warped, it becomes difficult to handle the silicon wafer after that and further it becomes difficult to convey the silicon wafer.
An object of the present invention is to provide a method of manufacturing a semiconductor device capable of being conveyed without occurrence of warping on a semiconductor substrate even if the thickness of the semiconductor substrate is reduced.
A method of manufacturing a semiconductor device, according to the present invention, comprises the steps of adhering a protection tape onto a first surface of a semiconductor substrate having a first surface having a plurality of semiconductor elements formed therein and a second surface opposite to the first surface, grinding the second surface of the semiconductor substrate, conveying the semiconductor substrate while controlling the temperature of the semiconductor substrate to prevent occurrence of warping, and separating the semiconductor substrate into the plurality of semiconductor elements.
In this arrangement, the semiconductor substrate, onto one surface of which the protection tape is adhered, and the opposite surface of which is ground, is conveyed to a next step while controlling (raising, for example), the temperature of the semiconductor substrate. There is a tendency that the semiconductor substrate is usually warped to the side onto which the protection tape is adhered, but when the protection tape is thermally expanded, the semiconductor substrate can be prevented from being warped onto the side on which the protection tape is adhered. In this way, the semiconductor substrate can be conveyed under the condition that no warping is caused on the semiconductor substrate.